The message warns that the worst-case scenario predicted by the influential scientific body Intergovernmental Panel on Climate Change (IPCC) is presently unfolding, with mean surface temperature and sea-level rises, ocean and ice-sheet dynamics and extreme weather conditions beyond their natural patterns.
The scientists say there is no excuse for inaction, because there are already many tools available to act on climate change and help reduce future social and economic costs significantly. They pointed out that even modest climate change effects are putting poor nations and communities at risk.
There are also equity issues at stake, as people experience different consequences of global warming even within individual countries and regions, the conference concluded. As the burden faced by the current and future generations will be very different, the experts called for a "common but differentiated mitigation strategy".
The conference's goal was to give a comprehensive picture of climate research carried out in the last two years, since the publication of the latest IPCC report (EurActiv 09/03/09). Its conclusions will be delivered to world decision-makers ahead of the Copenhagen climate conference (COP 15) in December.
Climate 'Marshall Plan' proposed
One of the highlights of the conference was the presentation of new findings showing that even the strictest greenhouse gas reduction targets can benefit the economy if supported by the right policies.
"Where many current calculations get it wrong is in the assumption that more stringent measures will necessarily raise the overall cost, especially when there is substantial unemployment and underuse of capacity, as there is today," said Terry Barker, director of the Cambridge Centre for Climate Change Mitigation Research, affiliated to the University of Cambridge.
Barker said there is now evidence that stricter targets can improve innovation and speed up the distribution of low-carbon technologies, while increasing government revenues from taxes and permit sales. The money, he stated, could be used to pay for new technologies and to lower other indirect taxes, "ensuring the fiscal neutrality of these measures".
According to Barker, the global financial crisis should be seen as a stimulus for coordinated action on climate change in the manner of US President Obama's 'Green New Deal'. The extra economic growth would in turn generate funds for helping developing countries adapt to the new conditions that are inevitably on the way.
"This 'New Marshall Plan' for the climate would be beneficial for all parties," said Barker.
Renewables potential 'exceeds previous estimates'
Scientists also presented positive evaluations of the viability of renewable energies. New research suggests that technologies such as wind and solar power could supply 40 percent of the world's electricity by 2050, if given adequate financial and political support. This contrasts sharply with previous estimations, which put the share of renewables at only 12% by 2030.
"Our findings demonstrate that with global political support and financial investment, previous notions that the potential for renewables was in some way limited to a negligible fraction of world demand were wrong," said Peter Lund of Helsinki's University of Technology.
Without the required push, though, these technologies risk being marginalised to a share of around 15%, the scientists said.